This invention relates to a typing device including a type disc having a plurality of different characters, each carried at the end of separate elastic bars forming part of the type disc. The type disc is rotatable and is arrested in its rotation at a predetermined position in which the desired character selected to be printed is in alignment with a hammer device which also forms part of the typing device. Upon actuating of a drive mechanism, the hammer is caused to hit the aligned bar of the desired character, thus pressing the latter against a record carrier supported on a platen.
In a known typing device of the above-outlined kind, as disclosed, for example, in U.S. Pat. No. 3,677,387, an electromagnet is de-energized by a signal, allowing a pivotal arm secured to the armature of the electromagnet to swing under the effect of a tension spring. The hammer secured at the end of the pivotal arm is thus moved rapidly against the respective elastic bar of the type disc. As a result, the desired character which, with its bar, has been brought into alignment with the hammer into the printing position, is pressed onto the record carrier held by the platen. This kind of typing device does not admit the control of the impact force of the hammer.
In power-driven typing devices having a single type disc, it is, because of the different printing surface areas of the different characters, highly desirable to control the impact force for the purpose of rendering the imprint uniform.